[clang-tools-extra] [clangd] Prevent printing huge initializer lists in hover definitions (PR #79746)

[Raoul Wols via cfe-commits]

https://github.com/rwols updated https://github.com/llvm/llvm-project/pull/79746

>From 1739d0a4fd079d2201e63166fbaba60644c52297 Mon Sep 17 00:00:00 2001
From: Raoul Wols <raoulwols at gmail.com>
Date: Sat, 10 Feb 2024 20:52:03 +0100
Subject: [PATCH] [clangd] Do not render large initializer expressions from the
 preamble

---
 clang-tools-extra/clangd/Hover.cpp            |  5 ++-
 .../clangd/unittests/HoverTests.cpp           | 35 +++++++++++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/clang-tools-extra/clangd/Hover.cpp b/clang-tools-extra/clangd/Hover.cpp
index 06b949bc4a2b55..2ff2416c3d68a8 100644
--- a/clang-tools-extra/clangd/Hover.cpp
+++ b/clang-tools-extra/clangd/Hover.cpp
@@ -143,8 +143,11 @@ std::string printDefinition(const Decl *D, PrintingPolicy PP,
       // Initializers might be huge and result in lots of memory allocations in
       // some catostrophic cases. Such long lists are not useful in hover cards
       // anyway.
-      if (200 < TB.expandedTokens(IE->getSourceRange()).size())
+      const auto &SM = VD->getASTContext().getSourceManager();
+      if (!SM.isInMainFile(VD->getLocation()) ||
+          200 < TB.expandedTokens(IE->getSourceRange()).size()) {
         PP.SuppressInitializers = true;
+      }
     }
   }
   std::string Definition;
diff --git a/clang-tools-extra/clangd/unittests/HoverTests.cpp b/clang-tools-extra/clangd/unittests/HoverTests.cpp
index 35db757b9c15b5..c1c986d1db3769 100644
--- a/clang-tools-extra/clangd/unittests/HoverTests.cpp
+++ b/clang-tools-extra/clangd/unittests/HoverTests.cpp
@@ -3956,6 +3956,41 @@ TEST(Hover, HideBigInitializers) {
   EXPECT_EQ(H->Definition, "int arr[]");
 }
 
+TEST(Hover, HideBigInitializersIncludedFromThePreamble) {
+  Annotations T(R"cpp(
+  #include "hugearray.h"
+  auto x = a^rr;
+  )cpp");
+  TestTU TU = TestTU::withCode(T.code());
+  TU.AdditionalFiles["hugearray.h"] = R"cpp(
+    #define A(x) x, x, x, x
+    #define B(x) A(A(A(A(x))))
+    int arr[256] = {B(0)};
+  )cpp";
+  auto AST = TU.build();
+  auto H = getHover(AST, T.point(), format::getLLVMStyle(), nullptr);
+  ASSERT_TRUE(H);
+  EXPECT_EQ(H->Definition, "int arr[256]");
+}
+
+// FIXME(rwols): Enable this test.
+TEST(Hover, DISABLED_DoNotHideSmallInitializersIncludedFromThePreamble) {
+  Annotations T(R"cpp(
+  #include "smallarray.h"
+  auto x = a^rr;
+  )cpp");
+  TestTU TU = TestTU::withCode(T.code());
+  TU.AdditionalFiles["smallarray.h"] = R"cpp(
+    #define A(x) x, x
+    #define B(x) A(A(x))
+    int arr[4] = {B(0)};
+  )cpp";
+  auto AST = TU.build();
+  auto H = getHover(AST, T.point(), format::getLLVMStyle(), nullptr);
+  ASSERT_TRUE(H);
+  EXPECT_EQ(H->Definition, "int arr[4] = {0, 0, 0, 0}");
+}
+
 #if defined(__aarch64__)
 // FIXME: AARCH64 sanitizer buildbots are broken after 72142fbac4.
 #define PREDEFINEMACROS_TEST(x) DISABLED_##x